TITLE: GCN CIRCULAR NUMBER: 11161 SUBJECT: GRB 100901A: MASTER Optical Early Limits DATE: 10/09/01 14:55:56 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs K.Ivanov, O.Chuvalaev, V.Poleschuk, E.Konstantinov, V.Lenok, O.Gres, S.Yazev, N.M.Budnev, Irkutsk State University E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina, D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov, D.Zimnukhov, M. Kornilov Sternberg Astronomical Institute, Moscow State University A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Yurkov, Yu.Sergienko, D.Varda, I.Kudelina Blagoveschensk Educational State University, Blagoveschensk V.Krushinski, I.Zalozhnich, T.Kopytova, A. Popov Ural State University, Kourovka Two MASTER robotic telescopes (MASTER-Net: http://observ.pereplet.ru) located near Baykal Lake (Tunka) and Blagoveschensk was pointed to the Swift GRB 100901A (Immler et al., GCN Circ 11159) 47 sec after Notice time (103 s after trigger time) and 45 s after Notice time (101s after trigger time). We have a number polarization, unfiltered and R images with exposition 20, 30, 40, 60... s. but near horizont. start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd? Filter -------------------------------------------------------------------------- 13:35:51 13:35:51 20 16.1 101.0 N Unfiltr 13:35:51 13:37:32 80 16.6 101.0 Y Unfiltr 13:35:53 13:36:13 20 16.5 103.0 N Polariz 13:35:53 13:38:02 90 17.4 103.0 Y Polariz The message may be cited. mailto: lipunov@sai.msu.ru